core: Move parameter validation from backend to core

Some functions (e.g. libusb_set_interface_alt_setting()) do not perform
sufficient parameter validation, leaving the burden on the backend to
catch invalid user input. Much of this validation is common across all
backends, yet not every backend implemented it. Fix this by moving
parameter validation to the core library functions.

This is also a good opportunity to remove the redundant
'num_configurations' field from the libusb_device structure. The value
of this field is already contained in the 'device_descriptor' member.

Signed-off-by: Chris Dickens <christopher.a.dickens@gmail.com>

5 files changed, 17 insertions, 44 deletions

diff --git a/libusb/os/haiku_usb_raw.cpp b/libusb/os/haiku_usb_raw.cpp
index 3162371..63efc17 100644
--- a/libusb/os/haiku_usb_raw.cpp
+++ b/libusb/os/haiku_usb_raw.cpp
@@ -97,7 +97,7 @@ haiku_get_config_descriptor(struct libusb_device *device, uint8_t config_index,
 	const usb_configuration_descriptor *config = dev->ConfigurationDescriptor(config_index);
 	if (config == NULL) {
 		usbi_err(DEVICE_CTX(device), "failed getting configuration descriptor");
-		return LIBUSB_ERROR_INVALID_PARAM;
+		return LIBUSB_ERROR_IO;
 	}
 	if (len > config->total_length) {
 		len = config->total_length;
diff --git a/libusb/os/sunos_usb.c b/libusb/os/sunos_usb.c
index 8d0c812..cd32f8b 100644
--- a/libusb/os/sunos_usb.c
+++ b/libusb/os/sunos_usb.c
@@ -1109,8 +1109,8 @@ sunos_set_configuration(struct libusb_device_handle *handle, int config)
 	if (dpriv->ugenpath == NULL)
 		return (LIBUSB_ERROR_NOT_SUPPORTED);
 
-	if (config < 1 || config > dpriv->dev_descr.bNumConfigurations)
-		return (LIBUSB_ERROR_INVALID_PARAM);
+	if (config < 1)
+		return (LIBUSB_ERROR_NOT_SUPPORTED);
 
 	dpriv->cfgvalue = config;
 	hpriv->config_index = config - 1;
@@ -1122,9 +1122,6 @@ int
 sunos_claim_interface(struct libusb_device_handle *handle, int iface)
 {
 	usbi_dbg("iface %d", iface);
-	if (iface < 0) {
-		return (LIBUSB_ERROR_INVALID_PARAM);
-	}
 
 	return (LIBUSB_SUCCESS);
 }
@@ -1135,9 +1132,6 @@ sunos_release_interface(struct libusb_device_handle *handle, int iface)
 	sunos_dev_handle_priv_t *hpriv = usbi_get_device_handle_priv(handle);
 
 	usbi_dbg("iface %d", iface);
-	if (iface < 0) {
-		return (LIBUSB_ERROR_INVALID_PARAM);
-	}
 
 	/* XXX: can we release it? */
 	hpriv->altsetting[iface] = 0;
@@ -1154,9 +1148,6 @@ sunos_set_interface_altsetting(struct libusb_device_handle *handle, int iface,
 
 	usbi_dbg("iface %d, setting %d", iface, altsetting);
 
-	if (iface < 0 || altsetting < 0) {
-		return (LIBUSB_ERROR_INVALID_PARAM);
-	}
 	if (dpriv->ugenpath == NULL)
 		return (LIBUSB_ERROR_NOT_FOUND);
 
diff --git a/libusb/os/windows_usbdk.c b/libusb/os/windows_usbdk.c
index 9c3e8fd..bb370ca 100644
--- a/libusb/os/windows_usbdk.c
+++ b/libusb/os/windows_usbdk.c
@@ -286,7 +286,6 @@ static void usbdk_device_init(libusb_device *dev, PUSB_DK_DEVICE_INFO info)
 	// Addresses in libusb are 1-based
 	dev->device_address = (uint8_t)(info->Port + 1);
 
-	dev->num_configurations = info->DeviceDescriptor.bNumConfigurations;
 	memcpy(&dev->device_descriptor, &info->DeviceDescriptor, LIBUSB_DT_DEVICE_SIZE);
 
 	switch (info->Speed) {
@@ -373,9 +372,6 @@ static int usbdk_get_config_descriptor(struct libusb_device *dev, uint8_t config
 	PUSB_CONFIGURATION_DESCRIPTOR config_header;
 	size_t size;
 
-	if (config_index >= dev->num_configurations)
-		return LIBUSB_ERROR_INVALID_PARAM;
-
 	config_header = (PUSB_CONFIGURATION_DESCRIPTOR)priv->config_descriptors[config_index];
 
 	size = min(config_header->wTotalLength, len);
@@ -390,7 +386,7 @@ static int usbdk_get_config_descriptor_by_value(struct libusb_device *dev, uint8
 	PUSB_CONFIGURATION_DESCRIPTOR config_header;
 	uint8_t index;
 
-	for (index = 0; index < dev->num_configurations; index++) {
+	for (index = 0; index < dev->device_descriptor.bNumConfigurations; index++) {
 		config_header = priv->config_descriptors[index];
 		if (config_header->bConfigurationValue == bConfigurationValue) {
 			*buffer = (unsigned char *)priv->config_descriptors[index];
diff --git a/libusb/os/windows_winusb.c b/libusb/os/windows_winusb.c
index ef6fbd2..245df90 100644
--- a/libusb/os/windows_winusb.c
+++ b/libusb/os/windows_winusb.c
@@ -681,27 +681,28 @@ static void cache_config_descriptors(struct libusb_device *dev, HANDLE hub_handl
 	struct libusb_context *ctx = DEVICE_CTX(dev);
 	struct winusb_device_priv *priv = usbi_get_device_priv(dev);
 	DWORD size, ret_size;
-	uint8_t i;
+	uint8_t i, num_configurations;
 
 	USB_CONFIGURATION_DESCRIPTOR_SHORT cd_buf_short; // dummy request
 	PUSB_DESCRIPTOR_REQUEST cd_buf_actual = NULL;    // actual request
 	PUSB_CONFIGURATION_DESCRIPTOR cd_data;
 
-	if (dev->num_configurations == 0)
+	num_configurations = priv->dev_descriptor.bNumConfigurations;
+	if (num_configurations == 0)
 		return;
 
 	assert(sizeof(USB_DESCRIPTOR_REQUEST) == USB_DESCRIPTOR_REQUEST_SIZE);
 
-	priv->config_descriptor = calloc(dev->num_configurations, sizeof(PUSB_CONFIGURATION_DESCRIPTOR));
+	priv->config_descriptor = calloc(num_configurations, sizeof(PUSB_CONFIGURATION_DESCRIPTOR));
 	if (priv->config_descriptor == NULL) {
 		usbi_err(ctx, "could not allocate configuration descriptor array for '%s'", priv->dev_id);
 		return;
 	}
 
-	for (i = 0; i <= dev->num_configurations; i++) {
+	for (i = 0; i <= num_configurations; i++) {
 		safe_free(cd_buf_actual);
 
-		if (i == dev->num_configurations)
+		if (i == num_configurations)
 			break;
 
 		size = sizeof(cd_buf_short);
@@ -860,13 +861,12 @@ static int init_device(struct libusb_device *dev, struct libusb_device *parent_d
 			}
 
 			memcpy(&priv->dev_descriptor, &(conn_info.DeviceDescriptor), sizeof(USB_DEVICE_DESCRIPTOR));
-			dev->num_configurations = conn_info.DeviceDescriptor.bNumConfigurations;
 			priv->active_config = conn_info.CurrentConfigurationValue;
 			if (priv->active_config == 0) {
 				usbi_dbg("0x%x:0x%x found %u configurations (not configured)",
 					priv->dev_descriptor.idVendor,
 					priv->dev_descriptor.idProduct,
-					dev->num_configurations);
+					priv->dev_descriptor.bNumConfigurations);
 				SleepEx(50, TRUE);
 			}
 		} while (priv->active_config == 0 && --ginfotimeout >= 0);
@@ -876,10 +876,10 @@ static int init_device(struct libusb_device *dev, struct libusb_device *parent_d
 				"forcing current configuration to 1",
 				priv->dev_descriptor.idVendor,
 				priv->dev_descriptor.idProduct,
-				dev->num_configurations);
+				priv->dev_descriptor.bNumConfigurations);
 			priv->active_config = 1;
 		} else {
-			usbi_dbg("found %u configurations (current config: %u)", dev->num_configurations, priv->active_config);
+			usbi_dbg("found %u configurations (current config: %u)", priv->dev_descriptor.bNumConfigurations, priv->active_config);
 		}
 
 		// Cache as many config descriptors as we can
@@ -957,7 +957,6 @@ static int enumerate_hcd_root_hub(struct libusb_context *ctx, const char *dev_id
 		usbi_dbg("assigning HCD '%s' bus number %u", dev_id, bus_number);
 		priv = usbi_get_device_priv(dev);
 		dev->bus_number = bus_number;
-		dev->num_configurations = 1;
 		priv->dev_descriptor.bLength = LIBUSB_DT_DEVICE_SIZE;
 		priv->dev_descriptor.bDescriptorType = LIBUSB_DT_DEVICE;
 		priv->dev_descriptor.bDeviceClass = LIBUSB_CLASS_HUB;
@@ -1543,10 +1542,6 @@ static int winusb_get_config_descriptor(struct libusb_device *dev, uint8_t confi
 	PUSB_CONFIGURATION_DESCRIPTOR config_header;
 	size_t size;
 
-	// config index is zero based
-	if (config_index >= dev->num_configurations)
-		return LIBUSB_ERROR_INVALID_PARAM;
-
 	if ((priv->config_descriptor == NULL) || (priv->config_descriptor[config_index] == NULL))
 		return LIBUSB_ERROR_NOT_FOUND;
 
@@ -1567,7 +1562,7 @@ static int winusb_get_config_descriptor_by_value(struct libusb_device *dev, uint
 	if (priv->config_descriptor == NULL)
 		return LIBUSB_ERROR_NOT_FOUND;
 
-	for (index = 0; index < dev->num_configurations; index++) {
+	for (index = 0; index < dev->device_descriptor.bNumConfigurations; index++) {
 		config_header = priv->config_descriptor[index];
 		if (config_header == NULL)
 			continue;
@@ -1641,9 +1636,6 @@ static int winusb_set_configuration(struct libusb_device_handle *dev_handle, int
 	struct winusb_device_priv *priv = usbi_get_device_priv(dev_handle->dev);
 	int r = LIBUSB_SUCCESS;
 
-	if (config >= USB_MAXCONFIG)
-		return LIBUSB_ERROR_INVALID_PARAM;
-
 	r = libusb_control_transfer(dev_handle, LIBUSB_ENDPOINT_OUT |
 		LIBUSB_REQUEST_TYPE_STANDARD | LIBUSB_RECIPIENT_DEVICE,
 		LIBUSB_REQUEST_SET_CONFIGURATION, (uint16_t)config,
@@ -2478,9 +2470,6 @@ static int winusbx_set_interface_altsetting(int sub_api, struct libusb_device_ha
 
 	CHECK_WINUSBX_AVAILABLE(sub_api);
 
-	if (altsetting > 255)
-		return LIBUSB_ERROR_INVALID_PARAM;
-
 	winusb_handle = handle_priv->interface_handle[iface].api_handle;
 	if (!HANDLE_VALID(winusb_handle)) {
 		usbi_err(HANDLE_CTX(dev_handle), "interface must be claimed first");
@@ -3592,9 +3581,6 @@ static int hid_set_interface_altsetting(int sub_api, struct libusb_device_handle
 
 	CHECK_HID_AVAILABLE;
 
-	if (altsetting > 255)
-		return LIBUSB_ERROR_INVALID_PARAM;
-
 	if (altsetting != 0) {
 		usbi_err(HANDLE_CTX(dev_handle), "set interface altsetting not supported for altsetting >0");
 		return LIBUSB_ERROR_NOT_SUPPORTED;
@@ -3615,7 +3601,7 @@ static int hid_submit_control_transfer(int sub_api, struct usbi_transfer *itrans
 	OVERLAPPED *overlapped;
 	int current_interface, config;
 	size_t size;
-	int r = LIBUSB_ERROR_INVALID_PARAM;
+	int r;
 
 	UNUSED(sub_api);
 	CHECK_HID_AVAILABLE;
diff --git a/libusb/os/windows_winusb.h b/libusb/os/windows_winusb.h
index c8d3f15..0340fe7 100644
--- a/libusb/os/windows_winusb.h
+++ b/libusb/os/windows_winusb.h
@@ -220,8 +220,8 @@ static inline void winusb_device_priv_release(struct libusb_device *dev)
 
 	free(priv->dev_id);
 	free(priv->path);
-	if ((dev->num_configurations > 0) && (priv->config_descriptor != NULL)) {
-		for (i = 0; i < dev->num_configurations; i++) {
+	if ((priv->dev_descriptor.bNumConfigurations > 0) && (priv->config_descriptor != NULL)) {
+		for (i = 0; i < priv->dev_descriptor.bNumConfigurations; i++) {
 			if (priv->config_descriptor[i] == NULL)
 				continue;
 			free((UCHAR *)priv->config_descriptor[i] - USB_DESCRIPTOR_REQUEST_SIZE);